drm/i915: properly disable the VDD when disabling the panel

Commit b3064154df tried to revert commit
dff392dbd2, but wasn't complete, which
resulted in regressions on Haswell. So this commit should fix
b3064154df by undoing what it did and
providing an actual complete revert of
dff392dbd2.

Fixes regression introduced by:
commit b3064154df
Author: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Date:   Tue Mar 4 00:42:44 2014 +0100
    drm/i915: Don't just say it, actually force edp vdd

Testcase: igt/pm_pc8
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Tested-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_ddi.c

@@ -1340,6 +1340,7 @@ static void intel_ddi_post_disable(struct intel_encoder *intel_encoder)
 	if (type == INTEL_OUTPUT_DISPLAYPORT || type == INTEL_OUTPUT_EDP) {
 		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
+		edp_panel_vdd_on(intel_dp);
 		intel_edp_panel_off(intel_dp);
 	}
 

drivers/gpu/drm/i915/intel_dp.c

@@ -91,7 +91,6 @@ static struct intel_dp *intel_attached_dp(struct drm_connector *connector)
 }
 
 static void intel_dp_link_down(struct intel_dp *intel_dp);
-static void edp_panel_vdd_on(struct intel_dp *intel_dp);
 static void edp_panel_vdd_off(struct intel_dp *intel_dp, bool sync);
 
 static int
@@ -1162,7 +1161,7 @@ static  u32 ironlake_get_pp_control(struct intel_dp *intel_dp)
 	return control;
 }
 
-static void edp_panel_vdd_on(struct intel_dp *intel_dp)
+void edp_panel_vdd_on(struct intel_dp *intel_dp)
 {
 	struct drm_device *dev = intel_dp_to_dev(intel_dp);
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1338,11 +1337,16 @@ void intel_edp_panel_off(struct intel_dp *intel_dp)
 
 	pp_ctrl_reg = _pp_ctrl_reg(intel_dp);
 
+	intel_dp->want_panel_vdd = false;
+
 	I915_WRITE(pp_ctrl_reg, pp);
 	POSTING_READ(pp_ctrl_reg);
 
 	intel_dp->last_power_cycle = jiffies;
 	wait_panel_off(intel_dp);
+
+	/* We got a reference when we enabled the VDD. */
+	intel_runtime_pm_put(dev_priv);
 }
 
 void intel_edp_backlight_on(struct intel_dp *intel_dp)
@@ -1880,7 +1884,6 @@ static void intel_disable_dp(struct intel_encoder *encoder)
 	intel_edp_backlight_off(intel_dp);
 	intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
 	intel_edp_panel_off(intel_dp);
-	edp_panel_vdd_off(intel_dp, true);
 
 	/* cpu edp my only be disable _after_ the cpu pipe/plane is disabled. */
 	if (!(port == PORT_A || IS_VALLEYVIEW(dev)))

drivers/gpu/drm/i915/intel_drv.h

@@ -767,6 +767,7 @@ void intel_edp_panel_off(struct intel_dp *intel_dp);
 void intel_edp_psr_enable(struct intel_dp *intel_dp);
 void intel_edp_psr_disable(struct intel_dp *intel_dp);
 void intel_edp_psr_update(struct drm_device *dev);
+void edp_panel_vdd_on(struct intel_dp *intel_dp);
 
 
 /* intel_dsi.c */